Although the liver of a healthy subject is able to regenerate itself by repairing or replacing injured or ill tissue, unfortunately once a certain amount of liver cells has died or has severely been damaged through disease or injuries, the whole organ may fail. Such a failure, be it an acute or chronic failure, may cause disease and death. The therapy of liver diseases encompasses conventional means, such as the administration of drugs. However, it is also state of the art to transplant livers or parts thereof. Furthermore, it is widely known to transplant liver cell populations in patients, such as described for instance in WO 2004/009766 A2. It is, however, still a major challenge in devising therapies for curing acute or chronic hepatic diseases to deliver liver cells to a patient in need thereof which methods are optimized in terms of viability, engraftment, proliferation and differentiation of the transplanted liver cells in the target tissue.
Haque et al. (Biotechnology Letters 27 (5) (2005), 317-322)) describe in vitro studies of alginate-chitosan microcapsules as an alternative to liver cell transplants for the treatment of liver failure. Chandrasekaran et al. (Tissue Engineering 12 (7), (2006)) disclose hepatic progenitor cells embedded in electrostatically produced beads.
In spite of the efforts to develop therapeutic systems which efficiently deliver liver cells into the patient's target tissue, there still remains the need to provide more reliable therapeutic means to cure liver diseases, in particular means which provide a high viability and physiological activity of the liver cells in the target body.